Central vacuum cleaning systems were originally quite simple. One placed a powerful central vacuum source external to the main living space. The source was connected through interior walls to a long flexible hose that terminated in a handle and nozzle. When an operator desired to use the system, the operator went to the source and turned it on. The operator then went inside, picked up the handle and directed the nozzle to an area to be cleaned.
Although many elements of the basic system remain, many improvements have been made. Rigid pipes typically run inside interior walls to numerous wall valves spaced throughout a building. This allows an operator to utilize a smaller hose while covering an equivalent space. This is an advantage as the hose can be quite bulky and heavy.
Various communication systems have been developed. Some systems sense sound or pressure in the pipes to turn the vacuum source on or off, see for example U.S. Pat. No. 5,924,164 issued 20 Jul. 1999 to Edward W. Lindsay under title ACOUSTIC COMMUNICATOR FOR CENTRAL VACUUM CLEANERS. Other systems run low voltage wires between the source and the wall valve. The source can be turned on and off at a wall valve by a switch that may be activated by insertion or removal of the hose. The hose may also contain low voltage wires to allow the source to be controlled from a switch in the handle, see for example U.S. Pat. No. 5,343,590 issued 6 Sep. 1994 to Kurtis R. Radabaugh under title LOW VOLTAGE CENTRAL VACUUM CONTROL HANDLE WITH AN AIR FLOW SENSOR. The switch can be a simple toggle switch, or a more sophisticated capacitive switch.
The low voltage wires running along the pipes can be replaced by conductive tape or the like on the pipes, see for example U.S. Pat. No. 4,854,887 issued 8 Aug. 1989 to Jean-Claude Blandin under title PIPE SYSTEM FOR CENTRAL SUCTION CLEANING INSTALLATION. Separate low voltage conductors in the walls can be avoided altogether by using mains power wires to transmit communication signals between the wall valve and the source, see for example U.S. Pat. No. 5,274,878 issued 4 Jan. 1994 to Kurtis R. Radabaugh, et al. under title REMOTE CONTROL SYSTEM FOR CENTRAL VACUUM SYSTEMS. A handheld radio frequency wireless transmitter can be used by an operator to turn the source on or off, see for example U.S. Pat. No. 3,626,545 issued 14 Dec. 1971 to Perry W. Sparrow under title CENTRAL VACUUM CLEANER WITH REMOTE CONTROL.
Line voltage can be brought adjacent the vacuum wall valves and connected to the handle through separate conductors, or integrated spiral wound conductors on the hose. Line voltage can then be brought from the handle to powered accessories, such as an electrically-powered beater bar, connected to the nozzle. Line voltage can be switched on and off to the powered accessory using the same switch in the handle that controls the source. Alternatively, the powered accessory may have its own power switch.
A control module mounted to the central vacuum unit is typically used to control the vacuum source. In an effort to increase suction, it is known to utilize two motors in a central vacuum unit under the control of the control module.
Improvements to, or additional or alternative features for, central vacuum cleaning systems are desirable.